Abstract

We have prepared plasma enhanced atomic layer deposition thin films by in situnitridation using nitrogen/oxygen mixture plasma and studied the effects of nitrogen contents and profiles on the negative bias temperature instability(NBTI). The nitrogen depth profiles and concentrations were controlled by changing the exposure sequences and the nitrogen to oxygen flow ratio, respectively. The best immunity to NBTI degradations was obtained for the nitrogen to oxygen ratio of 2:1 when nitrogen atoms are incorporated away from the high interface. We propose a dielectric degradation mechanism based on the reaction-diffusion model in which nitrogen plays a role of hydrogen generator at the interface and diffusion barrier in the bulk film.

Received 02 June 2008Accepted 17 July 2008Published online 22 September 2008

Acknowledgments:

This work was supported by Korea Research Foundation (MOEHRD) (Grant Nos. KRF-2005-005-J13102 and KRF-2007-331-D00243) and Korea Ministry of Commerce, Industry and Energy (System IC 2010, Commercialization Program of NanoProcess Equipments). Also, this work was supported by the Korea Science and Engineering Foundation (KOSEF) (Grant Nos. R01-2007-000-20143-0 and 2007-02864). Also, Mr. Maeng was financially supported by the second stage of the Brain Korea 21 project in 2007.